SonexBuilders.net

Root rib mod.

Many people have done this one, I’m talking about cutting away the web between the lightening holes in the root ribs to provide easier access later on when rigging the flaps.
Looks like a great idea.
People have also stated Sonex approves of this mod and they do it themselves (this can be seen in their wing install instruction sheet),
However it is not in the plans and no official documentation from Sonex is available on how to do this mod exactly.

I’ve seen different versions, some people install a doubler, some big, some smaller, others connect the flanges to make a big continuous flange around the entire cut-out, some do both, some do neither.

To clear this up I asked Kerry the question, here’s his reply, just thought I’d share because I’m sure he’s been asked the question before and no doubt he’ll be asked again, but maybe not as much now the reply is on this forum:

Hi Michael,

You have heard correctly.

You can cut the web out between the lightening holes and form a continuous flange around the entire cut-out. No additional doubler is necessary.

Blue Skies,

Kerry Fores

(I'll attach a picture once I've done mine)

I wish i had done this... rigging the flaps without it is a royal pain in the butt.

As promised, here's a picture:

Hey guys, real quick question. To do the mod, do I just need to cut up the forward ribs closest to the fuselage? That would leave me with a total of two modified forward ribs? One for the left wing and one for the right? Just trying to clarify....thanks!

Has anyone done this mod AFTER the wing is finished? (I am not even sure it is possible)

Robbie


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jmattson wrote:Hey guys, real quick question. To do the mod, do I just need to cut up the forward ribs closest to the fuselage? That would leave me with a total of two modified forward ribs? One for the left wing and one for the right? Just trying to clarify....thanks!

Correct, the left root rib and the right root rib.

As for doing this mod after the wing is complete, I think with care it shouldn't be terribly difficult. Just be sure you leave enough material to bend a continuous flange around the new hole.

Pictures of my mod here: http://www.rynoth.com/wordpress/waiex/2 ... root-ribs/